The Special Task Force of Kolkata police had arrested the six people from Assam in the last week of September for allegedly conspiring to carry out blasts in the country and also striking a deal with Bodo militants.

Of these, NIA took the custody of Moulana Yusuf, alleged to be the second-in-command of JMB's West Bengal unit and one of the main accused in the Burdwan blast, Jahidul Sheikh alias Zafar alias Jabirul, Mohammad Rafique, Shahidul alias Shamim and Abdul Kalam alias Kalim. Out of the five, Yusuf and Kalam had been chargesheeted by the NIA in abstentia while the role of other three would be ascertained after their interrogation, sources in the anti-terror probe agency said.

A Kolkata court handed over their custody to the NIA till October 27. Some of those arrested carried cash rewards, sources said. On October 2, 2014, a blast had occurred in a house at Khagragarh in which a man identified as Sakil Gazi died on the spot, while a man named Sovan Mandal died in hospital. Both of them were suspected of having terror links.

NIA later discovered that Mondal actually was Karim Sheikh and he had misled West Bengal police about his identity. The agency later filed a charge sheet against 30 people in March last year. Some others were added in supplementary charge sheets in which the NIA alleged that the JMB members wanted to establish Sharia rule by overthrowing the democratically-elected government in Bangladesh.

JMB's activities in India primarily included recruitment, radicalisation and training of vulnerable youths in a systematic and organised manner and, in pursuance of the conspiracy, they had established organisational bases in certain districts of West Bengal like Nadia, Burdwan,Murshidabad and Birbhum as well as in Sahebganj district of Jharkhand, the NIA said.